Antiviral Activity of Some Compounds of Gasteroid Mushrooms from Western Siberia.

The antiviral activity of aqueous and ethanol extracts from the fruiting bodies of gasteroid Basidiomy-cetes of Western Siberia: Lycoperdon pyriforme, Lycoperdon perlatum, and Phallus impudicus, as well as an aqueous extract from cultivated mycelium of P. impudicus and total polysaccharides from it, on MDCK cell culture against influenza A virus, was studied. Aqueous and ethanol extracts from the fruiting bodies of all studied gasteroid fungi showed antiviral activity against human influenza virus A/Aichi/2/68 (H3N2) and bird A/chicken/Kurgan/05/2005 virus (H5N1). At the same time, extracts from P. impudicus and L. pyriforme showed more pronouncing antiviral activity compared to the activity of the reference drug Tamiflu against the A/H5N1 avian influenza virus. A high antiviral efficacy of an aqueous extract from cultivated mycelium of the P. impudicus and a sample of total polysaccharides from this extract against the A/H5N1 avian influenza virus was revealed.

Substantial Antiviral Potential of Deoxyribozymes Fixed on Anatase Nanoparticles Against Influenza A Viruses in vitro and in vivo.

Influenza A viruses (IAV) are a high threat to humanity because of a lack of proper effective antiviral drugs and resistance of viruses to existing vaccines. We describe the sufficient anti-IAV effect of Ans/PL-Dz nanocomposites that contain deoxyribozymes (Dz) immobilized on anatase TiO2 nanoparticles (Ans) through polylysine linker (PL). The Dz-containing nanocomposites appear to be more efficient than the Ans/PL-ODN nanocomposites that contain common oligodeoxyribonucleotides (ODN) targeted to the same RNA regions of the viral genome. The simultaneous use of nanocomposites that contain Dz and ODN, which are targeted to different sites of viral RNA provides a higher overall effect than the independent action of each of them (synergism). The inhibition of IAV with the proposed nanocomposites was shown to be effective, sequence-specific, and dose-dependent. The most efficient Ans/PL-Dz nanocomposite exhibited a high antiviral effect in vivo on mice models. The efficiency of IAV inhibition with this nanocomposite in vitro and in vivo is higher than that for the approved antiflu drug oseltamivir. The results open the prospect of creating a unique antiviral agent suitable for IAV suppression.

Water Extract of the Chaga Medicinal Mushroom, Inonotus obliquus (Agaricomycetes), Inhibits SARS-CoV-2 Replication in Vero E6 and Vero Cell Culture Experiments.

The antiviral properties of water extracts from pharmaceutical raw materials of the chaga mushroom, Inonotus obliquus, were studied against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). All studies with infectious materials were carried out in an isolated virological laboratory of the State Research Center of Virology and Biotechnology Vector of Rospotrebnadzor, which has a sanitary and epidemiological conclusion for the right to work with pathogenic biological agents of I-II pathogenicity groups. Antiviral activity was determined by the ability of I. obliquus water extracts to inhibit the replication of SARS-CoV-2 (nCoV/Victoria /1/2020 strain) in Vero E6 and Vero cell cultures. The results of these studies showed that water extracts of I. obliquus are characterized by low toxicity in Vero and Vero E6 cell cultures and have antiviral activity against SARS-CoV-2. The 50% inhibitory concentration ranged from 0.75 to 11.6 µg/mL. A patent for the invention was received (Patent RU, 2741714 C 1, 2021).

Genome Features and In Vitro Activity against Influenza A and SARS-CoV-2 Viruses of Six Probiotic Strains.

PURPOSE: The aim of this work was to analyze the complete genome of probiotic bacteria Lactobacillus plantarum 8 RA 3, Lactobacillus fermentum 90 TC-4, Lactobacillus fermentum 39, Bifidobacterium bifidum 791, Bifidobacterium bifidum 1, and Bifidobacterium longum 379 and to test their activity against influenza A and SARS-CoV-2 viruses. METHODS: To confirm the taxonomic affiliation of the bacterial strains, MALDI TOF mass spectrometry and biochemical test systems were used. Whole genome sequencing was performed on the Illumina Inc. MiSeq platform. To determine the antiviral activity, A/Lipetsk/1V/2018 (H1N1 pdm09) (EPI_ISL_332798) and A/common gull/Saratov/1676/2018 (H5N6) (EPI_ISL_336925) influenza viruses and SARS-CoV-2 virus strain Australia/VIC01/2020 (GenBank: MT007544.1) were used. RESULTS: All studied probiotic bacteria are nonpathogenic for humans and do not contain the determinants of transmission-type antibiotic resistance and integrated plasmids. Resistance to antibiotics of different classes is explained by the presence of molecular efflux pumps of the MatE and MFS families. Cultures of L. fermentum 90 TC 4, L. plantarum 8 RA 3, and B. bifidum 791 showed a pronounced activity against influenza A viruses in MDCK cells. Activity against the SARS-CoV-2 virus was demonstrated only by the L. fermentum 90 TC 4 strain in VERO cells. CONCLUSIONS: The studied probiotic bacteria are safe, have antiviral activity, and are of great importance for the prevention of diseases caused by respiratory viruses that can also infect the human intestine.

High antiviral effect of TiO2·PL-DNA nanocomposites targeted to conservative regions of (-)RNA and (+)RNA of influenza A virus in cell culture.

Background: The development of new antiviral drugs based on nucleic acids is under scrutiny. An important problem in this aspect is to find the most vulnerable conservative regions in the viral genome as targets for the action of these agents. Another challenge is the development of an efficient system for their delivery into cells. To solve this problem, we proposed a TiO2·PL-DNA nanocomposite consisting of titanium dioxide nanoparticles and polylysine (PL)-containing oligonucleotides. Results: The TiO2·PL-DNA nanocomposites bearing the DNA fragments targeted to different conservative regions of (-)RNA and (+)RNA of segment 5 of influenza A virus (IAV) were studied for their antiviral activity in MDCK cells infected with the H1N1, H5N1, and H3N2 virus subtypes. Within the negative strand of each of the studied strains, the efficiency of DNA fragments increased in the direction of its 3'-end. Thus, the DNA fragment aimed at the 3'-noncoding region of (-)RNA was the most efficient and inhibited the reproduction of different IAV subtypes by 3-4 orders of magnitude. Although to a lesser extent, the DNA fragments targeted at the AUG region of (+)RNA and the corresponding region of (-)RNA were also active. For all studied viral subtypes, the nanocomposites bearing the DNA fragments targeted to (-)RNA appeared to be more efficient than those containing fragments aimed at the corresponding (+)RNA regions. Conclusion: The proposed TiO2·PL-DNA nanocomposites can be successfully used for highly efficient and site-specific inhibition of influenza A virus of different subtypes. Some patterns of localization of the most vulnerable regions in IAV segment 5 for the action of DNA-based drugs were found. The (-)RNA strand of IAV segment 5 appeared to be more sensitive as compared to (+)RNA.